用户登录记住密码

掌握 SharedPreferences 的使用

1.将所用到的图片素材粘贴到drawable，将登录页面进行设计，代码如下；

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:Android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:padding="@dimen/activity_horizontal_margin"    android:background="@drawable/logintop_roundbg"><EditText        android:id="@+id/etName"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:background="@android:drawable/edit_text"        android:drawableLeft="@drawable/icon_user"        android:drawablePadding="10dp"        android:ems="10"        android:hint="@string/etName">        <requestFocus />    </EditText>    <EditText        android:id="@+id/etPassword"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@id/etName"        android:background="@android:drawable/edit_text"        android:drawableLeft="@drawable/icon_pass"        android:drawablePadding="10dp"        android:ems="10"        android:hint="@string/ctPass">        <requestFocus />    </EditText>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@id/etPassword">        <CheckBox            android:text="记住密码"            android:layout_width="0dp"            android:layout_height="wrap_content"            android:id="@+id/cbIsRememberPass"            android:textSize="20sp"            android:layout_weight="1" />        <Button            android:layout_width="0dp"            android:layout_height="wrap_content"            android:layout_weight="1"            android:layout_marginLeft="10dp"            android:background="@drawable/btn_seclet"            android:onClick="login"            android:text="登录" />    </LinearLayout></RelativeLayout>

2.在Layout创建一个activity_main作为登录成功的欢迎界面，代码如下

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.example.administrator.case_login.MainActivity">    <TextView        android:text="Welcome you"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_centerHorizontal="true"        android:textSize="30sp"        android:layout_marginRight="129dp"        android:layout_marginEnd="129dp"        android:layout_marginTop="215dp"        android:id="@+id/textView" /></RelativeLayout>

在LoginActivity中配置

“`package com.example.administrator.case_login;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v4.content.SharedPreferencesCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends AppCompatActivity {
private EditText etName;
private EditText etPassword;
private CheckBox cbIsRememberPass;
private SharedPreferences sharedPreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);

    initViews();    sharedPreferences= getSharedPreferences("rememberpassword",Context.MODE_PRIVATE);    boolean isRemember=sharedPreferences.getBoolean("rememberpassword",false);    if(isRemember){        String name=sharedPreferences.getString("name","");        String password =sharedPreferences.getString("password","");        etName.setText(name);        etPassword.setText(password);        cbIsRememberPass.setChecked(true);    }}private void initViews(){    etName=(EditText)findViewById(R.id.etName);    etPassword=(EditText) findViewById(R.id.etPassword);    cbIsRememberPass=(CheckBox)findViewById(R.id.cbIsRememberPass);}public void login(View view){    String name=etName.getText().toString();    String password=etPassword.getText().toString();    if("admin".equals(name)&&"123456".equals(password)){        SharedPreferences.Editor editor=sharedPreferences.edit();        if(cbIsRememberPass.isChecked()){            editor.putBoolean("rememberpassword",true);            editor.putString("name",name);            editor.putString("password",password);        }else{            editor.clear();        }        editor.commit();        Intent intent=new Intent(this,MainActivity.class);        startActivity(intent);        finish();    }else{        Toast.makeText(this,"账号或密码有误", Toast.LENGTH_LONG).show();    }}

}

“
当用户选中了记住密码复选框，并成功登录一次之后，这个时候如果再重新启动登录界面，之前输入的用户名和密码就会显示在文本框中。